Components are sometimes coated on their surfaces with a material to locally modify the properties of the components. The surface coating of a component with a corrosion resistant material may increase the corrosion resistance of the component without sacrificing the beneficial properties of the material from which the component is made. An especially difficult environment to provide protection for a metal substrate is one which combines a high temperature corrosive ambient with wear, as occurs in turbocharger housings and exhaust components of internal combustion engine systems. A type of surface coating used in industry to increase corrosion and wear resistance of metal components is conversion coating. Conversion coating is surface coating where a part of the surface of the metal component is converted into the coating with a chemical or electro-chemical process.
As disclosed in U.S. Pat. No. 5,783,622 (the '622 patent), issued to Sabata et al. on Jul. 21, 1998, a chromate solution may be used as the corrosion resistant material to be applied to a component made of steel alloy. The chromate solution may be applied to the surface of the metal component by applying a layer of a liquid coating composition and then drying the applied solution. The drying may be performed by means of a heating method, including using an induction oven, where the maximum temperature attained may be less than 300° C.
Although the conversion coating of the '622 patent may be suitable for coating of a steel alloy surface, it may not be suitable for coating of a cast iron surface, for example. In addition, the conversion coating of the '622 patent may not be suitable for application where the maximum temperature of the heating method may be more than 300° C.
The devices and methods of the present disclosure are directed towards improvements in the existing technology.